1. Technical Field
The present invention relates to a method for making a light-emitting diode (LED) chip and the structure of the LED chip. More particularly, the present invention relates to a manufacturing method and a structure of an LED chip configured for illumination purposes.
2. Description of Related Art
Please refer to FIG. 1 for a sectional view of a conventional horizontal-structure LED unit 101 with parallel-connected LEDs. Manufacture of the LED unit 101 begins by forming an n-type semiconductor layer 111 on a gallium arsenide (GaAs) dielectric substrate 10, and a p-type semiconductor layer 112 on the n-type semiconductor layer 111. Then, an etching process is carried out to form a plurality of LEDs 11, which are subsequently connected in parallel by a first dielectric material 12 and a conductive layer 13. The LEDs 11 made by the TD process can only form a parallel-connected structure but cannot form a series-connected structure.
FIG. 2 is a sectional view of a conventional horizontal-structure LED unit 102 with parallel-connected LEDs made by the wafer bonding (WB) process. To make the LED unit 102 by the WB process, a second dielectric material 15 is formed on a metal or silicon substrate 14, then a p-type semiconductor layer 112 is formed on the second dielectric material 15, and an n-type semiconductor layer 111 is formed on the p-type semiconductor layer 112. Afterward, a plurality of LEDs 11 is formed by etching, and the LEDs 11 are connected in parallel by a first dielectric material 12 and a conductive layer 13. Again, the vertical LEDs 11 made by the WB process can form a parallel-connected structure but not a series-connected structure.
FIG. 3 is a sectional view of a conventional horizontal-structure LED unit 103 with series-connected LEDs made by the WB process. The WB-based manufacturing process includes forming a second dielectric material 15 on a metal or silicon substrate 14, forming a p-type semiconductor layer 112 on the second dielectric material 15, forming an n-type semiconductor layer 111 on the p-type semiconductor layer 112, forming a plurality of LEDs 11 by etching, and connecting the LEDs 11 in series by a first dielectric material 12 and a conductive layer 13.
According to the above, the conventional horizontal-structure LED unit 101 can only form a structure with parallel-connected LEDs (hereinafter referred to as a parallel-connected LED structure). Likewise, the conventional horizontal-structure LED units 102, 103 made by the WB process can only form either a parallel-connected LED structure or a structure with series-connected LEDs (hereinafter referred to as a series-connected LED structure); it is practically impossible to form a structure with series- and parallel-connected LEDs (hereinafter referred to as a series- and parallel-connected LED structure) in a single manufacturing process. As such, the conventional techniques leave much to be desired.